North America nebula (NGC 7000), located some 3000 light years away in the constellation of Cygnus. The North America nebula is classified as an HII region. It is formed by a cloud of gases, notably hydrogen, which are ionized by the ultraviolet radiation of a young, hot and massive star, located in the densest central region of the nebula. The average temperature of the nebula is about 10,000 Kelvin. Because hot, massive stars live for a short time, HII regions are also of recent origin (10 million years old). The nebula was named by the German astronomer Max Wolf, who, in 1890, photographed it for the first time.